text: #!/usr/bin/env python
  #
  #===- run-clang-tidy.py - Parallel clang-tidy runner ---------*- python -*--===#
  #
  #                     The LLVM Compiler Infrastructure
  #
  # This file is distributed under the University of Illinois Open Source
  # License. See LICENSE.TXT for details.
  #
  #===------------------------------------------------------------------------===#
  # FIXME: Integrate with clang-tidy-diff.py
  
  """
  Parallel clang-tidy runner
  ==========================
  
  Runs clang-tidy over all files in a compilation database. Requires clang-tidy
  and clang-apply-replacements in $PATH.
  
  Example invocations.
  - Run clang-tidy on all files in the current working directory with a default
    set of checks and show warnings in the cpp files and all project headers.
      run-clang-tidy.py $PWD
  
  - Fix all header guards.
      run-clang-tidy.py -fix -checks=-*,llvm-header-guard
  
  - Fix all header guards included from clang-tidy and header guards
    for clang-tidy headers.
      run-clang-tidy.py -fix -checks=-*,llvm-header-guard extra/clang-tidy \
                        -header-filter=extra/clang-tidy
  
  Compilation database setup:
  http://clang.llvm.org/docs/HowToSetupToolingForLLVM.html
  """
  
  import argparse
  import json
  import multiprocessing
  import os
  import Queue
  import re
  import shutil
  import subprocess
  import sys
  import tempfile
  import threading
  
  
  def find_compilation_database(path):
    """Adjusts the directory until a compilation database is found."""
    result = './'
    while not os.path.isfile(os.path.join(result, path)):
      if os.path.realpath(result) == '/':
        print 'Error: could not find compilation database.'
        sys.exit(1)
      result += '../'
    return os.path.realpath(result)
  
  
  def get_tidy_invocation(f, clang_tidy_binary, checks, tmpdir, build_path,
                          header_filter, extra_arg, extra_arg_before, quiet):
    """Gets a command line for clang-tidy."""
    start = [clang_tidy_binary]
    if header_filter is not None:
      start.append('-header-filter=' + header_filter)
    else:
      # Show warnings in all in-project headers by default.
      start.append('-header-filter=^' + build_path + '/.*')
    if checks:
      start.append('-checks=' + checks)
    if tmpdir is not None:
      start.append('-export-fixes')
      # Get a temporary file. We immediately close the handle so clang-tidy can
      # overwrite it.
      (handle, name) = tempfile.mkstemp(suffix='.yaml', dir=tmpdir)
      os.close(handle)
      start.append(name)
    for arg in extra_arg:
        start.append('-extra-arg=%s' % arg)
    for arg in extra_arg_before:
        start.append('-extra-arg-before=%s' % arg)
    start.append('-p=' + build_path)
    if quiet:
        start.append('-quiet')
    start.append(f)
    return start
  
  
  def apply_fixes(args, tmpdir):
    """Calls clang-apply-fixes on a given directory. Deletes the dir when done."""
    invocation = [args.clang_apply_replacements_binary]
    if args.format:
      invocation.append('-format')
      invocation.append('-style=file')
      invocation.append('-style-config=../')
    invocation.append(tmpdir)
    subprocess.call(invocation)
    shutil.rmtree(tmpdir)
  
  
  def run_tidy(args, tmpdir, build_path, queue):
    """Takes filenames out of queue and runs clang-tidy on them."""
    while True:
      name = queue.get()
      invocation = get_tidy_invocation(name, args.clang_tidy_binary, args.checks,
                                       tmpdir, build_path, args.header_filter,
                                       args.extra_arg, args.extra_arg_before,
                                       args.quiet)
      sys.stdout.write(' '.join(invocation) + '\n')
      subprocess.call(invocation)
      queue.task_done()
  
  
  def main():
    parser = argparse.ArgumentParser(description='Runs clang-tidy over all files '
                                     'in a compilation database. Requires '
                                     'clang-tidy and clang-apply-replacements in '
                                     '$PATH.')
    parser.add_argument('-clang-tidy-binary', metavar='PATH',
                        default='clang-tidy',
                        help='path to clang-tidy binary')
    parser.add_argument('-clang-apply-replacements-binary', metavar='PATH',
                        default='clang-apply-replacements',
                        help='path to clang-apply-replacements binary')
    parser.add_argument('-checks', default=None,
                        help='checks filter, when not specified, use clang-tidy '
                        'default')
    parser.add_argument('-header-filter', default=None,
                        help='regular expression matching the names of the '
                        'headers to output diagnostics from. Diagnostics from '
                        'the main file of each translation unit are always '
                        'displayed.')
    parser.add_argument('-j', type=int, default=0,
                        help='number of tidy instances to be run in parallel.')
    parser.add_argument('files', nargs='*', default=['.*'],
                        help='files to be processed (regex on path)')
    parser.add_argument('-fix', action='store_true', help='apply fix-its')
    parser.add_argument('-format', action='store_true', help='Reformat code '
                        'after applying fixes')
    parser.add_argument('-p', dest='build_path',
                        help='Path used to read a compile command database.')
    parser.add_argument('-extra-arg', dest='extra_arg',
                        action='append', default=[],
                        help='Additional argument to append to the compiler '
                        'command line.')
    parser.add_argument('-extra-arg-before', dest='extra_arg_before',
                        action='append', default=[],
                        help='Additional argument to prepend to the compiler '
                        'command line.')
    parser.add_argument('-quiet', action='store_true',
                        help='Run clang-tidy in quiet mode')
    args = parser.parse_args()
  
    db_path = 'compile_commands.json'
  
    if args.build_path is not None:
      build_path = args.build_path
    else:
      # Find our database
      build_path = find_compilation_database(db_path)
  
    try:
      invocation = [args.clang_tidy_binary, '-list-checks']
      invocation.append('-p=' + build_path)
      if args.checks:
        invocation.append('-checks=' + args.checks)
      invocation.append('-')
      print subprocess.check_output(invocation)
    except:
      print >>sys.stderr, "Unable to run clang-tidy."
      sys.exit(1)
  
    # Load the database and extract all files.
    database = json.load(open(os.path.join(build_path, db_path)))
    files = [entry['file'] for entry in database]
  
    max_task = args.j
    if max_task == 0:
      max_task = multiprocessing.cpu_count()
  
    tmpdir = None
    if args.fix:
      tmpdir = tempfile.mkdtemp()
  
    # Build up a big regexy filter from all command line arguments.
    file_name_re = re.compile('|'.join(args.files))
  
    try:
      # Spin up a bunch of tidy-launching threads.
      queue = Queue.Queue(max_task)
      for _ in range(max_task):
        t = threading.Thread(target=run_tidy,
                             args=(args, tmpdir, build_path, queue))
        t.daemon = True
        t.start()
  
      # Fill the queue with files.
      for name in files:
        if file_name_re.search(name):
          queue.put(name)
  
      # Wait for all threads to be done.
      queue.join()
  
    except KeyboardInterrupt:
      # This is a sad hack. Unfortunately subprocess goes
      # bonkers with ctrl-c and we start forking merrily.
      print '\nCtrl-C detected, goodbye.'
      if args.fix:
        shutil.rmtree(tmpdir)
      os.kill(0, 9)
  
    if args.fix:
      print 'Applying fixes ...'
      apply_fixes(args, tmpdir)
  
  if __name__ == '__main__':
    main()
  